CXCR5, also known as Burkitt lymphoma receptor (BLR1), CD185, MDR15 and MGC117347, is a G protein-coupled receptor which is a member of the CXC chemokine receptor family. A ligand is BLC, also known as CXCL13, which is a B cell chemoattractant. The unprocessed CXCR5 precursor is 372 amino acids in length with a molecular weight of 42 KD. CXCR5 has a role in B cell migration and localization within particular anatomic compartments. Knockout mice lack peripheral lymph nodes, have fewer Peyer's patches and have decreased B cell levels.